I prefer the Moab tested and approved versions:
I had started building a knockoff version of these trailers about a year ago right around the time my VX transmission blew up. Here's a LINK to the largely out of date buildup page(buildup starts at bottom of the page for some reason). I had wanted to ditch the built in tents these trailers feature due to the high costs and proprietary parts. Mine is going to be set up to simply deploy a 4ft.X 10ft. synthetic deck to put up a normal(small) tent on to get you up off of the cold, wet, typically critter infested ground. All in all, I only have bout $150 and lots of my time invested, so not bad.